Converting a JSON array stored in a local file to a TypeScript array within an Angular 5 project

Question

Converting a JSON array stored in a local file to a TypeScript array within an Angular 5 project

I'm currently working on developing a web app using Angular 5. My JSON file has the following structure:

[
  {
        "id": 0,
        "title": "Some title"
  },
  {
        "id": 1,
        "title": "Some title"
  },
  ...
]

The JSON file is stored locally, and I have an interface as well:

export interface Book {
  id: number;
  title: string;
}

My main questions revolve around how to:

Retrieve data from the JSON file?
Convert this data into an array of type Book[]?

javascript json angular typescript

Answer 1

Answer №1

To load the file, you can use the import method:

import data from 'path/to/data.json';

Then, you can assign this to an array of type Book[]:

@Component({...})
class Foo {
   books: Book[] = data;
}

Check out this demo for a live example.

In addition, include a wildcard module definition in your src/typings.d.ts file to guide the TypeScript compiler on how to import *.json files:

declare module "*.json" {
  const value: any;
  export default value;
}

Answer 2

To load the file, you can use the import method:

import data from 'path/to/data.json';

Then, you can assign this to an array of type Book[]:

@Component({...})
class Foo {
   books: Book[] = data;
}

Check out this demo for a live example.

In addition, include a wildcard module definition in your src/typings.d.ts file to guide the TypeScript compiler on how to import *.json files:

declare module "*.json" {
  const value: any;
  export default value;
}

Answer 3

Answer №2

This particular solution may be valuable to individuals, especially those dealing with Typescript 4 (while Angular 5 is compatible with Typescript 2).

Below is a snippet of the JSON file's contents (data.json):

[
  {
    "Gender": "Female",
    "HeightCm": 165,
    "WeightKg": 55
  },
  {
    "Gender": "Male",
    "HeightCm": 175,
    "WeightKg": 75
  }
]

Here is an essential tsconfig.json configuration:

{
    "compilerOptions": {  
      "strictNullChecks": true,
      "noImplicitAny": true
    } 
}

The following code snippet illustrates how to parse the JSON data into an interface Person:

import jsonData from './data.json';

interface Person {
    Gender: string;
    HeightCm: number;
    WeightKg: number;
}

const peopleArray: Person[] = jsonData as Person[];

Answer 4

This particular solution may be valuable to individuals, especially those dealing with Typescript 4 (while Angular 5 is compatible with Typescript 2).

Below is a snippet of the JSON file's contents (data.json):

[
  {
    "Gender": "Female",
    "HeightCm": 165,
    "WeightKg": 55
  },
  {
    "Gender": "Male",
    "HeightCm": 175,
    "WeightKg": 75
  }
]

Here is an essential tsconfig.json configuration:

{
    "compilerOptions": {  
      "strictNullChecks": true,
      "noImplicitAny": true
    } 
}

The following code snippet illustrates how to parse the JSON data into an interface Person:

import jsonData from './data.json';

interface Person {
    Gender: string;
    HeightCm: number;
    WeightKg: number;
}

const peopleArray: Person[] = jsonData as Person[];

Converting a JSON array stored in a local file to a TypeScript array within an Angular 5 project

Answer №1

Answer №2

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